/* ------------------------------------------------------------------------
 *
 * geqo_ox1.cpp
 *
 *	 order crossover [OX] routines;
 *	 OX1 operator according to Davis
 *	 (Proc Int'l Joint Conf on AI)
 *
 * IDENTIFICATION
 * src/gausskernel/optimizer/geqo/geqo_ox1.cpp
 *
 * -------------------------------------------------------------------------
 */
/* contributed by:
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
   *  Martin Utesch				 * Institute of Automatic Control	   *
   =							 = University of Mining and Technology =
   *  utesch@aut.tu-freiberg.de  * Freiberg, Germany				   *
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
 */
/* the ox algorithm is adopted from Genitor : */
/*************************************************************/
/* 															 */
/* 	Copyright (c) 1990										 */
/* 	Darrell L. Whitley										 */
/* 	Computer Science Department								 */
/* 	Colorado State University								 */
/* 															 */
/* 	Permission is hereby granted to copy all or any part of  */
/* 	this program for free distribution.   The author's name  */
/* 	and this copyright notice must be included in any copy.  */
/* 															 */
/*************************************************************/

#include "postgres.h"
#include "knl/knl_variable.h"
#include "optimizer/geqo_random.h"
#include "optimizer/geqo_recombination.h"

/* ox1
 *
 *	 position crossover
 */
void ox1(PlannerInfo* root, Gene* tour1, Gene* tour2, Gene* offspring, int num_gene, City* city_table)
{
    int left, right, k, p, temp;

    /* initialize city table */
    for (k = 1; k <= num_gene; k++)
        city_table[k].used = 0;

    /* select portion to copy from tour1 */
    left = geqo_randint(root, num_gene - 1, 0);
    right = geqo_randint(root, num_gene - 1, 0);
    if (left > right) {
        temp = left;
        left = right;
        right = temp;
    }

    /* copy portion from tour1 to offspring */
    for (k = left; k <= right; k++) {
        offspring[k] = tour1[k];
        city_table[(int)tour1[k]].used = 1;
    }

    k = (right + 1) % num_gene; /* index into offspring */
    p = k;                      /* index into tour2 */

    /* copy stuff from tour2 to offspring */
    while (k != left) {
        if (!city_table[(int)tour2[p]].used) {
            offspring[k] = tour2[p];
            k = (k + 1) % num_gene;
            city_table[(int)tour2[p]].used = 1;
        }
        p = (p + 1) % num_gene; /* increment tour2-index */
    }
}
